I supposed this should be in Car Audio, but I haven't researched that forum much and I don't know how "high end" they are over there. I might double-post. Anyway I've seen other auto sound posts here so...

I wanted some nice but not too pricey speakers to replace the factory cr@p in my '06 Ford Focus, and I also wanted to put them in the factory locations, so I got a pair each of the Peerless 830341 sale ($10.25) woofers and SEAS 27TAFNC/G aluminum tweeters.

I attached these to Scosche SA-68 adaptor plates - a direct drop-in replacement for the factory frames. The Peerless woofer was a perfect fit in these - I just needed to drill screw holes - I secured the woofers with basic nuts and bolts but used a little locktite on the threads for good measure.

The tweeters were more of a challenge - again, because I didn't want to cut out any holes in pillars or panels and run wire to new locations, and keep everything hidden away in the factory locations, I had to affix them to the adaptors also. They come with threaded holes on their underside, but I didn't have any bolts or screws of the same thread size for them; being too impatient and lazy to go to Home Depot and search for screws, I drilled holes in the adaptor plates just larger than the raised screw hole section that sticks up from the underside of the tweeter housing. Then I just dropped it into the little hole so that the flat bottom of the tweeter housing rests directly on the adaptor, and with a healthy dollop of JB Weld in between - let's just say they're not going anywhere.

Done after the pic was taken: I decided to cover the tweets with grille cloth to protect them from dust or whatever - I ran a bead of contact cement around the flanges and then stretched the fabric over them, then trimmed the edges - neat.

Now, in keeping with simplicity and economics there was no measuring or fancy crossover design here, especially given the tight spaces I had to work with. Madisound says the Peerless woofers are smooth out to 4.5k and may be used without a crossover - so that's what I did. I put an 80 Hz "bass blocker" cap on the positive lead, but no inductor to the woofers; after the split the tweeters were given 13 uF worth of electrolytic capacitor, providing first order attenuation around 3000 Hz - probably safe for this tweeter, as I don't plan to ever crank the volume to ridiculous levels, even when I get an aftermarket amp put in (factory unit is laughably anemic).

I didn't take any pics of the underside of the units, but the caps & wires were all fastened with thick double-sided tape and zip ties to the plate bottoms or woofer frames - it was actually very simple and easy, and all connections were soldered and covered with heat shrink tubing. Plenty of room for small parts under there but not much for inductors - so none was used.

When it came to actually dropping my custom speakers in the car doors the only issue was the factory wiring harnesses - they're little snap-together plugs. What I did was fabricate little "pins" from paper clips, soldered to the speaker lead wires, which fit quite snugly into the receptacles in the harnesses - I really had to pat myself on the back for that one - right before kicking myself in the rear when I realized I never had to make them in the first place - I only found out after installing them that there are adaptors for those too that have standard quick disconnect leads - but I still have to do the rear speakers so I will use a set then.

Listening impressions? The Peerless, despite their bargain basement price, are quite typical of their namesake, as well as are the SEAS tweeters - by far the most expensive components of the system, but at less than $30 per they are an exceptional value. Overall the speakers are very clean and satisfy my audiophile tastes for mobile sound.

Could they be better? I'm sure a more sophisticated crossover would help, but that is not in the current plans. The main disadvantage is that the speakers are in the doors and far below ear level; this is not so much an issue for the woofers but the tweeters are seriously off axis. A more ideal location would of course be higher up, facing the listener, but again that means cutting panels and I don't want to do that in my car. I can adjust the level on my head unit a bit, and without resistors the tweeters may be running a little "hot" anyway, so there may be some natural compensation built in.

What's next? Well it is a 4-channel system, and though I could repeat the same thing on the rear channels, I'm going to use them for bass only - I don't see the need for four fullranges plus separate sub - I'm the only person who's ever in the car and this will keep things simple and economical. I can't call them subs because I'm only using the 6.5" Silver Flute W17RC38 woofers, but they're the largest drivers that will fit in the factory locations, and they're a good value and I like their 5 mm X-max. I will use simple PE passive sub crossovers for them. No I don't expect to do any serious thumping and bumping with these, but with a compact car I expect they will give me all the bass I need for enjoyable listening.

Fortunately in my car the door panels are very easy to remove - no clips, just screws and a few snap-in tabs built into the inside of the panel that are very easy to align when replacing. There is very little effort involved in removing them.

I found a guide on how to do it on an owners' site for my car, and also instructions for removing the rear panels on another forum. So depending on what type of car you have the level of difficulty may vary, and without specific instructions I wouldn't risk trying to do it yourself - THAT's when you're likely to break something.

So I would start by Googling your model and maybe include "door panel removal" etc., but if it's at least four years old there will be repair manuals available at the auto parts stores, plus may be resources from the manufacturer.